Changing cache ownership in clustered multiprocessor

Abstract

Resolving coherency issues inherent in sharing distributed cache is described. A chip multiprocessor may include at least first and second processing clusters, each having multiple cores of a processor, multiple cache slices co-located with the multiple cores, and a memory controller (MC). The processor stores directory information in a memory coupled to the processor to indicate cluster cache ownership of a first address space to the first cluster. In response to a request to change the cluster cache ownership of the first address space, the processor may remap first lines of first cache slices, corresponding to the first address space, to second lines in second cache slices of the second cluster, and update the directory information (e.g., a state of the first cache lines) to change the cluster cache ownership of the first address space to the second cluster. One of the MCs may manage such updating of the directory.